1 /* $OpenBSD: imsg.c,v 1.13 2015/12/09 11:54:12 tb Exp $ */ 2 3 /* 4 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/types.h> 20 #include <sys/queue.h> 21 #include <sys/socket.h> 22 #include <sys/uio.h> 23 24 #include <errno.h> 25 #include <stdlib.h> 26 #include <string.h> 27 #include <unistd.h> 28 29 #include "imsg.h" 30 31 int imsg_fd_overhead = 0; 32 33 int imsg_get_fd(struct imsgbuf *); 34 35 void 36 imsg_init(struct imsgbuf *ibuf, int fd) 37 { 38 msgbuf_init(&ibuf->w); 39 memset(&ibuf->r, 0, sizeof(ibuf->r)); 40 ibuf->fd = fd; 41 ibuf->w.fd = fd; 42 ibuf->pid = getpid(); 43 TAILQ_INIT(&ibuf->fds); 44 } 45 46 ssize_t 47 imsg_read(struct imsgbuf *ibuf) 48 { 49 struct msghdr msg; 50 struct cmsghdr *cmsg; 51 union { 52 struct cmsghdr hdr; 53 char buf[CMSG_SPACE(sizeof(int) * 1)]; 54 } cmsgbuf; 55 struct iovec iov; 56 ssize_t n = -1; 57 int fd; 58 struct imsg_fd *ifd; 59 60 memset(&msg, 0, sizeof(msg)); 61 memset(&cmsgbuf, 0, sizeof(cmsgbuf)); 62 63 iov.iov_base = ibuf->r.buf + ibuf->r.wpos; 64 iov.iov_len = sizeof(ibuf->r.buf) - ibuf->r.wpos; 65 msg.msg_iov = &iov; 66 msg.msg_iovlen = 1; 67 msg.msg_control = &cmsgbuf.buf; 68 msg.msg_controllen = sizeof(cmsgbuf.buf); 69 70 if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL) 71 return (-1); 72 73 again: 74 if (getdtablecount() + imsg_fd_overhead + 75 (int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int)) 76 >= getdtablesize()) { 77 errno = EAGAIN; 78 free(ifd); 79 return (-1); 80 } 81 82 if ((n = recvmsg(ibuf->fd, &msg, 0)) == -1) { 83 if (errno == EINTR) 84 goto again; 85 goto fail; 86 } 87 88 ibuf->r.wpos += n; 89 90 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; 91 cmsg = CMSG_NXTHDR(&msg, cmsg)) { 92 if (cmsg->cmsg_level == SOL_SOCKET && 93 cmsg->cmsg_type == SCM_RIGHTS) { 94 int i; 95 int j; 96 97 /* 98 * We only accept one file descriptor. Due to C 99 * padding rules, our control buffer might contain 100 * more than one fd, and we must close them. 101 */ 102 j = ((char *)cmsg + cmsg->cmsg_len - 103 (char *)CMSG_DATA(cmsg)) / sizeof(int); 104 for (i = 0; i < j; i++) { 105 fd = ((int *)CMSG_DATA(cmsg))[i]; 106 if (ifd != NULL) { 107 ifd->fd = fd; 108 TAILQ_INSERT_TAIL(&ibuf->fds, ifd, 109 entry); 110 ifd = NULL; 111 } else 112 close(fd); 113 } 114 } 115 /* we do not handle other ctl data level */ 116 } 117 118 fail: 119 free(ifd); 120 return (n); 121 } 122 123 ssize_t 124 imsg_get(struct imsgbuf *ibuf, struct imsg *imsg) 125 { 126 size_t av, left, datalen; 127 128 av = ibuf->r.wpos; 129 130 if (IMSG_HEADER_SIZE > av) 131 return (0); 132 133 memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr)); 134 if (imsg->hdr.len < IMSG_HEADER_SIZE || 135 imsg->hdr.len > MAX_IMSGSIZE) { 136 errno = ERANGE; 137 return (-1); 138 } 139 if (imsg->hdr.len > av) 140 return (0); 141 datalen = imsg->hdr.len - IMSG_HEADER_SIZE; 142 ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE; 143 if (datalen == 0) 144 imsg->data = NULL; 145 else if ((imsg->data = malloc(datalen)) == NULL) 146 return (-1); 147 148 if (imsg->hdr.flags & IMSGF_HASFD) 149 imsg->fd = imsg_get_fd(ibuf); 150 else 151 imsg->fd = -1; 152 153 memcpy(imsg->data, ibuf->r.rptr, datalen); 154 155 if (imsg->hdr.len < av) { 156 left = av - imsg->hdr.len; 157 memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left); 158 ibuf->r.wpos = left; 159 } else 160 ibuf->r.wpos = 0; 161 162 return (datalen + IMSG_HEADER_SIZE); 163 } 164 165 int 166 imsg_compose(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid, 167 pid_t pid, int fd, const void *data, u_int16_t datalen) 168 { 169 struct ibuf *wbuf; 170 171 if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL) 172 return (-1); 173 174 if (imsg_add(wbuf, data, datalen) == -1) 175 return (-1); 176 177 wbuf->fd = fd; 178 179 imsg_close(ibuf, wbuf); 180 181 return (1); 182 } 183 184 int 185 imsg_composev(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid, 186 pid_t pid, int fd, const struct iovec *iov, int iovcnt) 187 { 188 struct ibuf *wbuf; 189 int i, datalen = 0; 190 191 for (i = 0; i < iovcnt; i++) 192 datalen += iov[i].iov_len; 193 194 if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL) 195 return (-1); 196 197 for (i = 0; i < iovcnt; i++) 198 if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1) 199 return (-1); 200 201 wbuf->fd = fd; 202 203 imsg_close(ibuf, wbuf); 204 205 return (1); 206 } 207 208 /* ARGSUSED */ 209 struct ibuf * 210 imsg_create(struct imsgbuf *ibuf, u_int32_t type, u_int32_t peerid, 211 pid_t pid, u_int16_t datalen) 212 { 213 struct ibuf *wbuf; 214 struct imsg_hdr hdr; 215 216 datalen += IMSG_HEADER_SIZE; 217 if (datalen > MAX_IMSGSIZE) { 218 errno = ERANGE; 219 return (NULL); 220 } 221 222 hdr.type = type; 223 hdr.flags = 0; 224 hdr.peerid = peerid; 225 if ((hdr.pid = pid) == 0) 226 hdr.pid = ibuf->pid; 227 if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) { 228 return (NULL); 229 } 230 if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1) 231 return (NULL); 232 233 return (wbuf); 234 } 235 236 int 237 imsg_add(struct ibuf *msg, const void *data, u_int16_t datalen) 238 { 239 if (datalen) 240 if (ibuf_add(msg, data, datalen) == -1) { 241 ibuf_free(msg); 242 return (-1); 243 } 244 return (datalen); 245 } 246 247 void 248 imsg_close(struct imsgbuf *ibuf, struct ibuf *msg) 249 { 250 struct imsg_hdr *hdr; 251 252 hdr = (struct imsg_hdr *)msg->buf; 253 254 hdr->flags &= ~IMSGF_HASFD; 255 if (msg->fd != -1) 256 hdr->flags |= IMSGF_HASFD; 257 258 hdr->len = (u_int16_t)msg->wpos; 259 260 ibuf_close(&ibuf->w, msg); 261 } 262 263 void 264 imsg_free(struct imsg *imsg) 265 { 266 free(imsg->data); 267 } 268 269 int 270 imsg_get_fd(struct imsgbuf *ibuf) 271 { 272 int fd; 273 struct imsg_fd *ifd; 274 275 if ((ifd = TAILQ_FIRST(&ibuf->fds)) == NULL) 276 return (-1); 277 278 fd = ifd->fd; 279 TAILQ_REMOVE(&ibuf->fds, ifd, entry); 280 free(ifd); 281 282 return (fd); 283 } 284 285 int 286 imsg_flush(struct imsgbuf *ibuf) 287 { 288 while (ibuf->w.queued) 289 if (msgbuf_write(&ibuf->w) <= 0) 290 return (-1); 291 return (0); 292 } 293 294 void 295 imsg_clear(struct imsgbuf *ibuf) 296 { 297 int fd; 298 299 msgbuf_clear(&ibuf->w); 300 while ((fd = imsg_get_fd(ibuf)) != -1) 301 close(fd); 302 } 303